Photopolymerized Thermosensitive Poly(HPMAlactate)-PEG-Based Hydrogels: Effect of Network Design on Mechanical Properties, Degradation, and Release Behavior

• Published in: Biomacromolecules Vol. 11; no. 8; pp. 2143 - 2151
• Main Authors: Censi, Roberta, Vermonden, Tina, Deschout, Hendrik, Braeckmans, Kevin, di Martino, Piera, De Smedt, Stefaan C, van Nostrum, Cornelus F, Hennink, Wim E
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 09.08.2010
• Subjects: Acrylamides - chemistry; Applied sciences; Biological and medical sciences; Drug Delivery Systems; Exact sciences and technology; General pharmacology; Hydrogels; Magnetic Resonance Spectroscopy; Medical sciences; Microscopy, Confocal; Molecular Weight; Organic polymers; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Physicochemistry of polymers; Polyethylene Glycols - chemistry; Properties and characterization; Rheology; Serum Albumin, Bovine - chemistry; Solution and gel properties; Biological properties; Viscoelasticity; Photochemical crosslinking; Biodegradability; Control release polymer; Composition effect; Drug carrier; Serum albumin; Ethylene oxide copolymer; Experimental study; In vitro; Esterification; Colloidal gel; Methacrylamide derivative copolymer; Triblock copolymer; Chemical modification; Free radical polymerization; Preparation; Kinetics; Methacrylate copolymer; Release; Microheterogeneity
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm100514p

Photopolymerized thermosensitive A-B-A triblock copolymer hydrogels composed of poly(N-(2-hydroxypropyl)methacrylamide lactate) A-blocks, partly derivatized with methacrylate groups to different extents (10, 20, and 30%) and hydrophilic poly(ethylene glycol) B-blocks of different molecular weights (4, 10, and 20 kDa) were synthesized. The aim of the present study was to correlate the polymer architecture with the hydrogel properties, particularly rheological, swelling, degradation properties and release behavior. It was found that an increasing methacrylation extent and a decreasing PEG molecular weight resulted in increasing gel strength and cross-link density, which tailored the degradation profiles from 25 to more than 300 days. Polymers having small PEG blocks showed a remarkable phase separation into polymer- and water-rich domains, as demonstrated by confocal microscopy. Depending on the hydrophobic domain density, the loaded protein resides in the hydrophilic pores or is partitioned into hydrophilic and hydrophobic domains, and its release from these compartments is tailored by the extent of methacrylation and by PEG length, respectively. As the mechanical properties, degradation, and release profiles can be fully controlled by polymer design and concentration, these hydrogels are suitable for controlled protein release.